1. Field of the Invention
This invention relates to a knitting machine, especially a straight knitter, and to knitting machines having a stopping mechanism for a slide movable longitudinally on the knitting machine and which may be triggered in the event of danger of pinching of the operator s hand.
2. Description of the Prior Art
Knitting machines of this kind are disclosed in the publication "Strickerei-und Wirkerei-Technik", the issue of April 1963, No. 4. In such a knitting machine, a stopping mechanism is triggered to terminate movement of a movable part of the machine relative to a fixed part to provide protection against possible pinching of the operator's hand during manipulations while knitting is being carried out.
In the production of flat textile materials in meter runs of semi-regular goods or fully regular goods on straight knitters, it is always desirable and necessary to be able to continously supervise production. Any defects that may occur must be rapidly detected and must be capable of being removed. The more the knitting machine is open and readily accessible, the greater are the possibilities of effecting control and the easier it is for the operator to take steps to correct the operation of the knitting machine during knitting. One such step is necessary, for example, when the goods are to be pressed down between the combs by means of the stroking device during movement of the slide so as to permit dealing with bunching of the knitted material. Such stroking device, or stroker/sinker, is mounted in the stead of a yarn carrier to precede another carier, while feeding yarn, and engage the fabric, thereby precluding upward fabric movement with the needles.
An open design type of knitting machine permitting ready accessibility while the machine is operating, inevitably exposes the operator to danger since a number of places where pinching of the operator's hand can occur, cannot be avoided, particularly between the slide of the knitting machine and stationary parts secured to the machine frame. Hitherto, no means have been disclosed for preventing injuries by such pinching which have proved popular in practice.
A known protective arrangement consists in the provision of a fixed shield, cover or hood. Such covers have been found by the operators to constitute a hindrance to manipulations on the machine after the machine has been put into operation, and the operator in many cases simply sets the cover aside because of the inconvenience which the cover causes.
Also, large hinge hoods which cover the entire working area of the knitting machine are also known and oftentimes employed. However, such hoods have not been acceptable to the operators, particularly to the knitters since they do not permit any visual inspection whatsoever of the knitting machine when it is operating. Furthermore, it is impossible to adjust the operation of the machine unless the hoods are first removed.
Finally, use has been made of safety arrangements in the form of light-barrier systems built into the knitting machine. Such systems too suffer from the more serious of the above mentioned disadvantages, particularly the impossibility of adjusting the operation of the machine without switching off the light barriers.
The object of the present invention is to provide a safety device for a knitting machine that not only provides protection against injury, particularly injuries at places where pinching of the operator's hand may occur between the slide and other fixed parts on the machine frame, but also a device which is totally acceptable to the machine operator and is not circumvented by such operator.
According to the invention, this object is achieved by the employment of a hood which is mounted on the slide, movable with the slide and also movable relative to the slide in a direction in which the latter moves and is further mounted so as to be swung up transversely to the direction in which the slide moves in a contact device for triggering the stopping mechanism of the knitting machine provided on the end faces of the hood as viewed in the direction in which the slide travels. Further, the hood is displaceable relative to the slide through a distance corresponding to the braking distance of the slide after the stopping mechanism has been triggered.
In the safety device of the present invention, the contact devices trigger the stopping mechanism of the knitting machine when danger arises as to the possibility of occurrence of a pinching action, for example, of the hand of the operator between the slide and a stationary part of the machine frame. While the slide is then travelling over its braking distance, the hood does not continue to move on account of contact resistance but deflects to an extent corresponding to the braking distance of the slide so that no pinching can take place. The device includes means permitting the hood to be swung up transversely to the direction of movement of the slide and offers the advantage of also avoiding injury when the knitting operator exposed to possible danger in the moment of alarm withdraws his or her from the danger zone. If such a movement is made, the hood simply deflects upwardly.
The hood is expediently, rectilinearly displaceable relative to the slide in the direction of movement of the slide or it may be swivelable in the direction of movement of that slide. The possible distance of translatory or swivel movement of the hood relative to the slide is advantageously equal to the braking distance of the slide at the greatest possible velocity of slide movement. This insures that even at the highest possible slide speed, no pinching can take place despite the triggering of the stopping mechanism for the slide.
The contact devices at the respective end faces of the hood advantageously may consist of an air hose which is connected to a pressure-wave switch of the known variety. The high switching sensitivity obtainable with pressure-wave switches in conjunction with air hoses insures rapid actuation or triggering of the stopping mechanism of the knitting machine.
In accordance with a further feature of the invention, contact bars are also provided in the zone where the knitting machine is operated, which contact bars when lightly touched or slightly pressed, enable the triggering of the stopping mechanism for the knitting machine. This arrangement provides still greater safety for the operators. The contact bars in the zone where the knitting machine is operated also preferably consist of an air hose connected to a pressure-wave switch.